jtm60????rectifier???

[Jay101]

I have pulled out power pcb and noticed a lot of discoloration under the rectifier. Also the sloder has pushed out flux on the power tube sockets I know I know yes the tubes were hot plated....But what would common symtoms of rectifer failure?? or capacitor failure?? The rec. pins have a blueish tint to them also... My hopes are to get a rectifer replace it and the caps also if i can find them put her back together n jam well is dosent hurt to hope...right???Also does any one have a good link for caps I found a couple but none had the same size and well the jtm has heat issues and the ones i found are shorter and fatter moving them closer to other componets.
Thanks in advance for any advice..101

[Rockn]

Rectifier failure

Common symptoms would be no power to any other components in the amp or incorrect bias voltages to the other tubes. Do you know what values you need for the power filter caps?

[Jay101]

cap info

550 vdc
47 micro f
thanks

[Rockn]

Rectum...damn near killed em

So this is a solid state rectifier and not tube rectifier? That cap sounds like something other than a power filter cap. Those caps are usually very large with what for your amp is probably 2 - 100 mfd 350v in series or 2 - 50mfd 500v caps in parallel.

If you have a volt meter you can test the diodes with it set to ohms and it will only show resistance in one direction. If any of them show as a short in both directions your rectifier is shot....assuming it is a SS rectifier.

[Jay101]

thanks

thamks i meant to post this thread in trouble shooting sorry i may copy this and move it thanks again

[Jay101]

bump

bump

[Albert Kreuzer]

Hi Jay,

would you mind to tell as what the problem was in the first place?
I mean, like "no sound" or "no B+" or "smoke coming out"

Cheers,
Albert

[Jay101]

albert

i tried to bump this thread after you sugesed that i keep only one thread you have responded to the other and thank you very much..

[torcamaniac]

Hi Jay,

I've just done a few mods to my JTM 60 and also changed the original big blue filter caps. I couldn't find them anywhere except on TAD (Tube amp doctor). If you still need them check the site out.

[oc disorder]

I think you will find the bridge rectifier you are referring to if you trace it feeds a DC heater voltage to pre-amp tubes 1,2,3 & 4.

http://bmamps.com/Schematics/marshal...60w_jtm600.pdf.

The rectifying diodes for the HT are D105,106,107,108.

Is there a fault?

[torcamaniac]

I think you will find the bridge rectifier you are referring to if you trace it feeds a DC heater voltage to pre-amp tubes 1,2,3 & 4.

http://bmamps.com/Schematics/marshal...60w_jtm600.pdf.

The rectifying diodes for the HT are D105,106,107,108.

Is there a fault?

It is a bridge rectifier in one piece. In a case.
But one could solder 4 diodes as rectifier and replace it.

[g1]

Before anyone else jumps in, this thread was resolved in 2009.